For example, Power Protein's chicken burrito packs 24 grams of protein, and its steak burrito packs the same. Calories are 400 and 420, respectively. That might compare to the calorie count of the standard menu's XXL Grilled Stuffed Burrito (Beef), which has 890 calories.

Taco Bell, in a news release, said it knows its customers' tastes and needs are evolving, as are their dietary preferences. This is the first Taco Bell menu to be created, it said, with "new nutritional guardrails in mind."

As part of the same test, Taco Bell said it also will offer new, health-conscious beverage choices, including two zero-calorie, non-carbonated drinks: diet green tea and pomegranate SoBe Lifewater.

The new menu items will be tested for about five to six weeks, said the company, then likely will graduate to the standard menu in 2014.

With the healthy, however, comes the less so: The advent Power Protein coincides with the return to the standard menu of an item guaranteed to make Richard Simmons faint: Taco Bell's Fritos-stuffed Beefy Crunch Burrito with cheese sauce: 510 calories, 200 of those from fat. Protein? Just 14 grams.

"We're not perfect," Taco Bell CEO Greg Creed told The Associated Press in a conference call. "We're just trying to get better."